November 2025 - Devel - libvirt List Archives

[ PATCH vf-token 0/8] Introduce vf-token when using userspace PF
by Vivek Kashyap 23 Dec '25

23 Dec '25

The VFIO PCI ABI has been extended to require userspace PF driver to set a VF token to a known value. The VF drivers are then required to provide this token to access the VF device. The vf-token is set by the PF driver before VF drivers can access the device. The kernel provides no means to retrieve the token in use; but there is no specification describing the distribution or level of confidentiality of the token. Qemu has been extended to require the vf-token when vf device is used. An important point to note is that the vf-token is required only when both the PF and VF are used in userspace. This patch series adds support to provide the vf-token (uuid format) in the domain XML and to generate the qemu commandline including the vf-token. To support vf-token the new element will be used as follows: <hostdev mode='subsystem' type='pci' managed='yes'> <driver name='vfio'/> <source> <address domain='0x0000' bus='0x0' slot='0x00' function='0x1'> <vf-token uuid='00112233-4455-6677-8899-aabbccddeeff'/> </address> </source> <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x0'/> </hostdev> The generated commandline will include the following: -device {"driver":"vfio-pci","host":"0000:00:0.1", "vf-token":"00112233-4455-6677-8899-aabbccddeeff", "id":"hostdev0","bus":"pci.0","addr":"0x1"} Changes since initial RFC based on review comments received: 1. Added documentation 2. Added test cases and ran successful test suite after each patch commit 3. fixed spaces, coding sytle, and uuid string format 4. Used S:vftoken in virJSONValueObjectAdd instead of a conditional Vivek Kashyap (8): Define the vf-token extension for PCI device Introduce the vf-token qemu capability This patch introduces the PCI address extension flag for vf-token This patch introduces new XML parser/formatter functions for parsing the vf-token Introduce a validation function for vf-token support in qemu and generate vf-token device attribute in qemu command line Provide information about the vf-token flag Add tests for the vf-token flag to the qemuxml2argv and qemuxml2xml test suites Update news about vf-token NEWS.rst | 8 +++ docs/formatdomain.rst | 3 ++ src/conf/device_conf.c | 49 ++++++++++++++++--- src/conf/domain_addr.h | 1 + src/conf/domain_conf.c | 8 +++ src/conf/schemas/basictypes.rng | 7 +++ src/libvirt_private.syms | 1 + src/qemu/qemu_capabilities.c | 3 ++ src/qemu/qemu_capabilities.h | 1 + src/qemu/qemu_command.c | 8 +++ src/qemu/qemu_domain_address.c | 3 ++ src/qemu/qemu_validate.c | 20 ++++++++ src/util/virpci.c | 7 +++ src/util/virpci.h | 10 ++++ .../qemucapabilitiesdata/caps_8.1.0_s390x.xml | 1 + .../caps_8.1.0_x86_64.xml | 1 + .../caps_8.2.0_x86_64.xml | 1 + .../hostdev-vfio-vf-token.x86_64-latest.args | 34 +++++++++++++ .../hostdev-vfio-vf-token.xml | 22 +++++++++ tests/qemuxml2argvtest.c | 1 + .../hostdev-vfio-vf-token.x86_64-latest.xml | 40 +++++++++++++++ tests/qemuxml2xmltest.c | 1 + 22 files changed, 223 insertions(+), 7 deletions(-) create mode 100644 tests/qemuxml2argvdata/hostdev-vfio-vf-token.x86_64-latest.args create mode 100644 tests/qemuxml2argvdata/hostdev-vfio-vf-token.xml create mode 100644 tests/qemuxml2xmloutdata/hostdev-vfio-vf-token.x86_64-latest.xml -- 2.33.8

3 19

[PATCH v2 0/5] qemu: Implement support for iommufd
by Nathan Chen 18 Dec '25

18 Dec '25

Hi, This is a follow up to the first patch series [0] for using iommufd to propagate DMA mappings to the kernel for VM-assigned host devices in a qemu VM. We add a new 'iommufd' attribute for hostdev devices to be associated with the iommufd object. For instance, specifying the iommufd object and associated hostdev in a VM definition: <devices> ... <hostdev mode='subsystem' type='pci' managed='no'> <driver iommufd='yes'/> <source> <address domain='0x0009' bus='0x01' slot='0x00' function='0x0'/> </source> <address type='pci' domain='0x0000' bus='0x15' slot='0x00' function='0x0'/> </hostdev> <hostdev mode='subsystem' type='pci' managed='no'> <driver iommufd='yes'/> <source> <address domain='0x0019' bus='0x01' slot='0x00' function='0x0'/> </source> <address type='pci' domain='0x0000' bus='0x16' slot='0x00' function='0x0'/> </hostdev> ... </devices> This would get translated to a qemu command line with the arguments below. Note that libvirt will open the /dev/iommu and VFIO cdev, passing the associated fd number to qemu: -object '{"qom-type":"iommufd","id":"iommufd0","fd":"24"}' \ -device '{"driver":"vfio-pci","host":"0009:01:00.0","id":"hostdev0","iommufd":"iommufd0","fd":"22","bus":"pci.21","addr":"0x0"}' \ -device '{"driver":"vfio-pci","host":"0019:01:00.0","id":"hostdev1","iommufd":"iommufd0","fd":"25","bus":"pci.22","addr":"0x0"}' \ Note that when Libvirt launches the qemu process as an unprivileged user, i.e. libvirt-qemu, it is bound by the RLIMIT_MEMLOCK limit calculated based on how much RAM is assigned to the VM. IOMMUFD's unified memory accounting causes ENOMEM errors for large device BARs that exceed the process memlock limit. VFIO without IOMMUFD does not check device memory against the limit and therefore does not show this behavior. To work around the issue, we can specify CAP_IPC_LOCK=ep capability for the qemu binary to bypass the RLIMIT_MEMLOCK limit. I am working on a long-term fix in the kernel to mark device memory regions so they do not count against the RLIMIT_MEMLOCK limit for how much memory can be locked/pinned, as I/O device BARs do not consume host RAM. This series is on Github: https://github.com/NathanChenNVIDIA/libvirt/tree/iommufd-11-25 Thanks, Nathan [0] https://lists.libvirt.org/archives/list/devel@lists.libvirt.org/thread/MYPM… Signed-off-by: Nathan Chen <nathanc(a)nvidia.com> Nathan Chen (5): qemu: Implement support for associating iommufd to hostdev qemu: open VFIO FDs from libvirt backend qemu: open iommufd FD from libvirt backend qemu: Update Cgroup, namespace, and seclabel for iommufd tests: qemuxmlconfdata: provide iommufd sample XML and CLI args docs/formatdomain.rst | 8 + src/conf/device_conf.c | 12 ++ src/conf/device_conf.h | 1 + src/conf/domain_conf.h | 2 + src/conf/schemas/basictypes.rng | 5 + src/libvirt_private.syms | 1 + src/qemu/qemu_cgroup.c | 26 +-- src/qemu/qemu_command.c | 53 ++++- src/qemu/qemu_domain.c | 40 ++++ src/qemu/qemu_domain.h | 19 ++ src/qemu/qemu_namespace.c | 16 +- src/qemu/qemu_process.c | 186 ++++++++++++++++++ src/security/security_apparmor.c | 18 +- src/security/security_dac.c | 28 ++- src/security/security_selinux.c | 28 ++- src/security/virt-aa-helper.c | 11 +- src/util/virpci.c | 69 +++++++ src/util/virpci.h | 2 + .../iommufd-q35.x86_64-latest.args | 41 ++++ .../iommufd-q35.x86_64-latest.xml | 60 ++++++ tests/qemuxmlconfdata/iommufd-q35.xml | 38 ++++ .../iommufd-virt.aarch64-latest.args | 33 ++++ .../iommufd-virt.aarch64-latest.xml | 34 ++++ tests/qemuxmlconfdata/iommufd-virt.xml | 22 +++ .../iommufd.x86_64-latest.args | 35 ++++ .../qemuxmlconfdata/iommufd.x86_64-latest.xml | 38 ++++ tests/qemuxmlconfdata/iommufd.xml | 30 +++ tests/qemuxmlconftest.c | 33 ++++ 28 files changed, 839 insertions(+), 50 deletions(-) create mode 100644 tests/qemuxmlconfdata/iommufd-q35.x86_64-latest.args create mode 100644 tests/qemuxmlconfdata/iommufd-q35.x86_64-latest.xml create mode 100644 tests/qemuxmlconfdata/iommufd-q35.xml create mode 100644 tests/qemuxmlconfdata/iommufd-virt.aarch64-latest.args create mode 100644 tests/qemuxmlconfdata/iommufd-virt.aarch64-latest.xml create mode 100644 tests/qemuxmlconfdata/iommufd-virt.xml create mode 100644 tests/qemuxmlconfdata/iommufd.x86_64-latest.args create mode 100644 tests/qemuxmlconfdata/iommufd.x86_64-latest.xml create mode 100644 tests/qemuxmlconfdata/iommufd.xml -- 2.43.0

2 15

[PATCH 1/3] bhyve: implement SLIRP networking
by Roman Bogorodskiy 16 Dec '25

16 Dec '25

Bhyve supports SLIRP networking using the following syntax: -s 12:0,e1000,slirp,open Where "e1000" is a NIC model, "slirp" is the SLIRP backend and "open" specifies open mode where external network is available to the guest. The "open" mode is a recent addition in FreeBSD -CURRENT. Unfortunately, bhyve does not provide a way to probe whether the open mode is supported, so users will have to make sure it's supported on their own. For the reference, without the "open" mode, the guest will have no outside network connectivity. To make this mode useful, it is possible to configure forwarding from the host to the guest, but it is not covered by this patch. Signed-off-by: Roman Bogorodskiy <bogorodskiy(a)gmail.com> --- src/bhyve/bhyve_command.c | 6 +++- .../bhyvexml2argv-slirp.args | 10 ++++++ .../bhyvexml2argv-slirp.ldargs | 4 +++ .../bhyvexml2argvdata/bhyvexml2argv-slirp.xml | 21 ++++++++++++ tests/bhyvexml2argvtest.c | 1 + .../bhyvexml2xmlout-slirp.xml | 32 +++++++++++++++++++ tests/bhyvexml2xmltest.c | 1 + 7 files changed, 74 insertions(+), 1 deletion(-) create mode 100644 tests/bhyvexml2argvdata/bhyvexml2argv-slirp.args create mode 100644 tests/bhyvexml2argvdata/bhyvexml2argv-slirp.ldargs create mode 100644 tests/bhyvexml2argvdata/bhyvexml2argv-slirp.xml create mode 100644 tests/bhyvexml2xmloutdata/bhyvexml2xmlout-slirp.xml diff --git a/src/bhyve/bhyve_command.c b/src/bhyve/bhyve_command.c index e42e7b1ecc..b7e47084e6 100644 --- a/src/bhyve/bhyve_command.c +++ b/src/bhyve/bhyve_command.c @@ -93,9 +93,13 @@ bhyveBuildNetArgStr(const virDomainDef *def, goto cleanup; } break; + case VIR_DOMAIN_NET_TYPE_USER: + virCommandAddArg(cmd, "-s"); + virCommandAddArgFormat(cmd, "%d:0,%s,slirp,open", + net->info.addr.pci.slot, nic_model); + return 0; case VIR_DOMAIN_NET_TYPE_ETHERNET: case VIR_DOMAIN_NET_TYPE_DIRECT: - case VIR_DOMAIN_NET_TYPE_USER: case VIR_DOMAIN_NET_TYPE_VHOSTUSER: case VIR_DOMAIN_NET_TYPE_SERVER: case VIR_DOMAIN_NET_TYPE_CLIENT: diff --git a/tests/bhyvexml2argvdata/bhyvexml2argv-slirp.args b/tests/bhyvexml2argvdata/bhyvexml2argv-slirp.args new file mode 100644 index 0000000000..ff9a90ebc9 --- /dev/null +++ b/tests/bhyvexml2argvdata/bhyvexml2argv-slirp.args @@ -0,0 +1,10 @@ +bhyve \ +-c 1 \ +-m 214 \ +-u \ +-H \ +-P \ +-s 0:0,hostbridge \ +-s 2:0,ahci,hd:/tmp/freebsd.img \ +-s 3:0,e1000,slirp,open \ +bhyve diff --git a/tests/bhyvexml2argvdata/bhyvexml2argv-slirp.ldargs b/tests/bhyvexml2argvdata/bhyvexml2argv-slirp.ldargs new file mode 100644 index 0000000000..5905f4b3e6 --- /dev/null +++ b/tests/bhyvexml2argvdata/bhyvexml2argv-slirp.ldargs @@ -0,0 +1,4 @@ +bhyveload \ +-m 214 \ +-d /tmp/freebsd.img \ +bhyve diff --git a/tests/bhyvexml2argvdata/bhyvexml2argv-slirp.xml b/tests/bhyvexml2argvdata/bhyvexml2argv-slirp.xml new file mode 100644 index 0000000000..5cf13d2a20 --- /dev/null +++ b/tests/bhyvexml2argvdata/bhyvexml2argv-slirp.xml @@ -0,0 +1,21 @@ +<domain type='bhyve'> + <name>bhyve</name> + <uuid>df3be7e7-a104-11e3-aeb0-50e5492bd3dc</uuid> + <memory>219136</memory> + <vcpu>1</vcpu> + <os> + <type>hvm</type> + </os> + <devices> + <disk type='file'> + <driver name='file' type='raw'/> + <source file='/tmp/freebsd.img'/> + <target dev='hda' bus='sata'/> + <address type='drive' controller='0' bus='0' target='2' unit='0'/> + </disk> + <interface type='user'> + <model type='e1000'/> + <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> + </interface> + </devices> +</domain> diff --git a/tests/bhyvexml2argvtest.c b/tests/bhyvexml2argvtest.c index 650313c2da..ee3d677947 100644 --- a/tests/bhyvexml2argvtest.c +++ b/tests/bhyvexml2argvtest.c @@ -270,6 +270,7 @@ mymain(void) DO_TEST("sata-rotation-rate"); DO_TEST_FAILURE("disk-virtio-rotation-rate"); DO_TEST_FAILURE("disk-virtio-queue-opts"); + DO_TEST("slirp"); /* Address allocation tests */ DO_TEST("addr-single-sata-disk"); diff --git a/tests/bhyvexml2xmloutdata/bhyvexml2xmlout-slirp.xml b/tests/bhyvexml2xmloutdata/bhyvexml2xmlout-slirp.xml new file mode 100644 index 0000000000..44d2616f6c --- /dev/null +++ b/tests/bhyvexml2xmloutdata/bhyvexml2xmlout-slirp.xml @@ -0,0 +1,32 @@ +<domain type='bhyve'> + <name>bhyve</name> + <uuid>df3be7e7-a104-11e3-aeb0-50e5492bd3dc</uuid> + <memory unit='KiB'>219136</memory> + <currentMemory unit='KiB'>219136</currentMemory> + <vcpu placement='static'>1</vcpu> + <os> + <type arch='x86_64'>hvm</type> + <boot dev='hd'/> + </os> + <clock offset='utc'/> + <on_poweroff>destroy</on_poweroff> + <on_reboot>restart</on_reboot> + <on_crash>destroy</on_crash> + <devices> + <disk type='file' device='disk'> + <driver name='file' type='raw'/> + <source file='/tmp/freebsd.img'/> + <target dev='hda' bus='sata'/> + <address type='drive' controller='0' bus='0' target='2' unit='0'/> + </disk> + <controller type='pci' index='0' model='pci-root'/> + <controller type='sata' index='0'> + <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/> + </controller> + <interface type='user'> + <mac address='52:54:00:00:00:00'/> + <model type='e1000'/> + <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> + </interface> + </devices> +</domain> diff --git a/tests/bhyvexml2xmltest.c b/tests/bhyvexml2xmltest.c index c2458b9fc4..0abc50b0de 100644 --- a/tests/bhyvexml2xmltest.c +++ b/tests/bhyvexml2xmltest.c @@ -122,6 +122,7 @@ mymain(void) DO_TEST_DIFFERENT("nvme"); DO_TEST_DIFFERENT("2-nvme-2-controllers"); DO_TEST_DIFFERENT("passthru-multiple-devs"); + DO_TEST_DIFFERENT("slirp"); /* Address allocation tests */ DO_TEST_DIFFERENT("addr-single-sata-disk"); -- 2.51.2

3 9

Question about error conditions for ACPI usage on aarch64
by Kazuhiro Abe (Fujitsu) 16 Dec '25

16 Dec '25

Hi all, We are currently working on CCA support. Due to CCA specifications, we are unable to use pflash with QEMU. Therefore, we intend to enable ACPI by specifying the UEFI firmware using the QEMU -bios option as follows: -machine virt,acpi=on -bios /usr/share/qemu-efi-aarch64/QEMU_EFI.fd Using the above QEMU option, we can successfully boot VM. My understanding is that the above QEMU option could be translated by the following libvirt XML: <os> <type arch='aarch64' machine='virt-4.0'>hvm</type> <loader type="rom">/usr/share/qemu-efi-aarch64/QEMU_EFI.fd</loader> </os> <features> <acpi/> </features> However, this XML configuration results in a validation error. Specifically, the error occurs because def->os.firmware is VIR_DOMAIN_OS_DEF_FIRMWARE_NONE during the following check: src/qemu/qemu_validate.c: qemuValidateDomainDef() /* On aarch64, ACPI requires UEFI */ if (def->features[VIR_DOMAIN_FEATURE_ACPI] == VIR_TRISTATE_SWITCH_ON && def->os.arch == VIR_ARCH_AARCH64 && (def->os.firmware != VIR_DOMAIN_OS_DEF_FIRMWARE_EFI && !virDomainDefHasOldStyleUEFI(def))) { virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", _("ACPI requires UEFI on this architecture")); return -1; } It appears that a configuration that successfully boots QEMU directly is being rejected by libvirt. Could you please explain if there's a specific reason for this strict validation? We are particularly interested in why VIR_DOMAIN_OS_DEF_FIRMWARE_NONE also becomes a condition for this error. Best Regards, Kazuhiro Abe

3 9

[RFC v3 0/5] cover: RFE libvirt secret encryption on disk
by Arun Menon 03 Dec '25

03 Dec '25

Libvirt secrets are stored unencrypted on the disk. With this series we want to start encrypting the secrets. 1. Introduce the GnuTLS decryption wrapper functions that work exact opposite to the encryption wrappers. 2. Add a new service called virt-secrets-init-encryption, that is linked to the virtsecretd service. virtsecretd service only starts after the new service generates a random encryption key. 3. Add a new secrets.conf configuration file that helps user to set a. secrets_encryption_key - allows the user to specify the encryption key file path, in case the default key is not to be used. b. encrypt_data - set to 0 or 1. If set to 1, then the newly added secrets will be encrypted. 4. Add encryption scheme or cipher attribute that will allow us to choose the last used cipher. 5. Once we have the encryption key, and a reliable way to tell the daemon what encryption scheme the secret object is using, we can encrypt the secrets on disk and store them in <uuid>.<encryption_scheme> format. It is important to note that if the encryption key is changed between restarts, then the respective secret will not be loaded by the driver. This is a sincere attempt to improve upon the already submitted patch https://lists.libvirt.org/archives/list/devel@lists.libvirt.org/thread/KE6G… Resolves: https://issues.redhat.com/browse/RHEL-7125 --- Changes in v3: - Secrets xml configuration no longer stores the encryption scheme, therefore not allowing the user to toggle between ciphers. - Removed unnecessary socket files of the new service. It now has a general configuration with which it starts. - Addressed review comments from Peter on coding style and design. - Loading of secrets is dependent on the file extension. Most recent cipher is used while saving the secrets. Changes in v2: - Corrected the encryption key length check. It should be 32. - Added a new patch that introduces the encryption scheme attribute. This will help us identify which secrets are encrypted. - A new systemd unit service file added that starts before virtsecretd, helping us to construct a random encryption key and pass it to the virtsecretd service. - Parsing logic of secrets.conf moved to a separate file. - Spec file changes, augeas. Arun Menon (5): util: Add support for GnuTLS decryption secret: Set up default encryption secret key for the virtsecretd service secret: Add secrets.conf configuration file and parse it secret: Add encryptionSchemeType attribute to store ciphers secret: Add functionality to load and save secrets in encrypted format include/libvirt/libvirt-secret.h | 20 +++ libvirt.spec.in | 7 + po/POTFILES | 1 + src/conf/meson.build | 1 + src/conf/secret_conf.h | 1 + src/conf/secret_config.c | 177 ++++++++++++++++++++++++ src/conf/secret_config.h | 38 +++++ src/conf/virsecretobj.c | 177 ++++++++++++++++++------ src/conf/virsecretobj.h | 13 +- src/libvirt_private.syms | 3 + src/meson.build | 1 + src/secret/libvirt_secrets.aug | 40 ++++++ src/secret/meson.build | 42 ++++++ src/secret/secret-init-encryption.in | 10 ++ src/secret/secret_driver.c | 27 +++- src/secret/secrets.conf.in | 12 ++ src/secret/test_libvirt_secrets.aug.in | 6 + src/secret/virtsecretd.service.extra.in | 8 ++ src/util/vircrypto.c | 126 ++++++++++++++++- src/util/vircrypto.h | 8 ++ src/util/virsecret.c | 4 + src/util/virsecret.h | 1 + tests/vircryptotest.c | 65 +++++++++ 23 files changed, 735 insertions(+), 53 deletions(-) create mode 100644 src/conf/secret_config.c create mode 100644 src/conf/secret_config.h create mode 100644 src/secret/libvirt_secrets.aug create mode 100644 src/secret/secret-init-encryption.in create mode 100644 src/secret/secrets.conf.in create mode 100644 src/secret/test_libvirt_secrets.aug.in -- 2.51.1

3 21

[PATCH 0/8] Avoid changing const string via strchr() and friends
by Michal Privoznik 02 Dec '25

02 Dec '25

This stems from the discussion here: https://lists.libvirt.org/archives/list/devel@lists.libvirt.org/thread/HVMC… Green pipeline here: https://gitlab.com/MichalPrivoznik/libvirt/-/pipelines/2183169334 Michal Prívozník (8): vircommand: Update documentation to virCommandSetDryRun() virstringtest: Introduce a test for virSkipSpacesBackwards() virfirewalltest: Introduce testIPtablesSetupPrivateChains() virSkipSpacesBackwards: Turn @endp into const iptablesPrivateChainCreate: Rename @tmp variable iptablesPrivateChainCreate: Switch to STRSKIP() iptablesPrivateChainCreate: Avoid modifying const string lib: Avoid changing const strings via strchr() and friends src/interface/interface_backend_udev.c | 2 +- src/libxl/xen_common.c | 10 +- src/libxl/xen_xm.c | 10 +- src/network/meson.build | 1 + src/network/network_iptables.c | 33 ++++--- src/node_device/node_device_udev.c | 2 +- src/nwfilter/nwfilter_ebiptables_driver.c | 4 +- src/qemu/qemu_monitor_json.c | 2 +- src/qemu/qemu_nbdkit.c | 2 +- src/rpc/virnetsshsession.c | 5 +- src/storage/storage_util.c | 2 +- src/storage_file/storage_source.c | 4 +- src/util/vircgroup.c | 2 +- src/util/vircommand.c | 10 +- src/util/virfile.c | 2 +- src/util/virstoragefile.c | 4 +- src/util/virstring.c | 20 ++-- src/util/virstring.h | 2 +- src/util/virsysinfo.c | 22 ++--- src/util/virxml.c | 3 +- src/vmware/vmware_conf.c | 2 +- tests/meson.build | 9 +- tests/virfirewalltest.c | 111 ++++++++++++++++++++++ tests/virstringtest.c | 48 ++++++++++ tools/vsh.c | 6 +- 25 files changed, 252 insertions(+), 66 deletions(-) -- 2.51.2

3 11

[RFC PATCH v3 0/4] qemu: Implement support for EGM
by Nathan Chen 02 Dec '25

02 Dec '25

The Grace SOC introduces Extended GPU Memory (EGM) [3], a feature that enables GPUs to efficiently access system memory within and across nodes. This patch series adds support for virtualizing EGM (vEGM) in libvirt, allowing VMs to utilize dedicated EGM memory regions through ACPI. This patch series is a follow-up RFC to the second EGM RFC series [0], to gather feedback from the libvirt community on the overall approach and implementation details. While kernel EGM driver support and QEMU acpi-egm-memory device support are not yet upstream, reference implementations are available [1][2] to enable testing and validation of the libvirt integration. Any community feedback is appreciated. Background and Use Cases ========================= EGM allows host memory to be partitioned into two regions: 1. Standard memory for Host OS usage 2. EGM region assigned to VMs as their system memory This technology enables various high-performance computing scenarios [3]: - Large memory pools for AI/ML workloads - High-performance computing applications - Memory extension for systems with limited main memory - GPU-accelerated workloads requiring large addressable memory Implementation Overview ======================= This series adds a new memory device model VIR_DOMAIN_MEMORY_MODEL_EGM with 'path' source attribute and 'pciDev' target attribute to denote host EGM device backing path and PCI device alias to associate the vEGM with, respectively. For instance, given the XML stanzas below: <memory model='egm' access='shared'> <source> <path>/dev/egm4</path> </source> <target> <size unit='KiB'>8388608</size> <node>0</node> <pciDev>ua-hostdev0</pciDev> </target> </memory> <memory model='egm' access='shared'> <source> <path>/dev/egm5</path> </source> <target> <size unit='KiB'>8388608</size> <node>1</node> <pciDev>ua-hostdev1</pciDev> </target> </memory> The corresponding qemu command line will include the following arguments: -object '{"qom-type":"memory-backend-file","id":"memegm0","mem-path":"/dev/egm4","share":true,"prealloc":true,"size":8589934592}' \ -object acpi-egm-memory,id=egm0,pci-dev=ua-hostdev0,node=0 \ -object '{"qom-type":"memory-backend-file","id":"memegm1","mem-path":"/dev/egm5","share":true,"prealloc":true,"size":8589934592}' \ -object acpi-egm-memory,id=egm1,pci-dev=ua-hostdev1,node=1 \ -numa node,nodeid=0,cpus=0-1,memdev=memegm4 \ -numa node,nodeid=1,cpus=2-3,memdev=memegm5 \ For a system where multiple GPUs are associated with a single host socket/NUMA node/EGM chardev, we consolidate the memory backing into a single memory-backend-file object per host EGM chardev. For instance, given the XML stanzas below: <memory model='egm' access='shared'> <source> <path>/dev/egm4</path> </source> <target> <size unit='KiB'>8388608</size> <node>0</node> <pciDev>ua-hostdev0</pciDev> </target> </memory> <memory model='egm' access='shared'> <source> <path>/dev/egm4</path> </source> <target> <size unit='KiB'>8388608</size> <node>0</node> <pciDev>ua-hostdev1</pciDev> </target> </memory> The corresponding qemu command line will include the following arguments: -object '{"qom-type":"memory-backend-file","id":"memegm0","mem-path":"/dev/egm4","share":true,"prealloc":true,"size":17179869184}' \ -object acpi-egm-memory,id=egm0,pci-dev=ua-hostdev0,node=0 \ -object acpi-egm-memory,id=egm1,pci-dev=ua-hostdev1,node=0 \ -numa node,nodeid=0,cpus=0-4,memdev=memegm0 \ Changes from RFCv2: - Decouple host EGM chardev name from guest EGM ID - Consolidate all acpi-egm-memory objects' memory into a single memory-backend-file per EGM chardev specified. Changes from RFCv1: - Use existing memory device infrastructure to represent EGM configuration - Added support for multiple EGM devices This series is on Github: https://github.com/NathanChenNVIDIA/libvirt/tree/egm-11-24-25 Thanks, Nathan [0] https://lists.libvirt.org/archives/list/devel@lists.libvirt.org/thread/6RU7… [1] https://github.com/ianm-nv/qemu/tree/6.8_ghvirt_egm_may2025 [2] https://github.com/NVIDIA/QEMU/commit/32db1b74fb99c0571724c7e69485e89098c14… [3] https://developer.nvidia.com/blog/nvidia-grace-hopper-superchip-architectur… Ian May (1): tests: Add qemuxmlconftest for ACPI EGM memory device Nathan Chen (3): conf: Support EGM memory device model qemu: Add cgroup, namespace, and seclabel setup for EGM memory device model qemu: Add qemu CLI support for EGM docs/formatdomain.rst | 18 +- src/conf/domain_conf.c | 34 +++- src/conf/domain_conf.h | 7 + src/conf/domain_postparse.c | 6 +- src/conf/domain_validate.c | 15 ++ src/conf/schemas/domaincommon.rng | 6 + src/qemu/qemu_alias.c | 7 +- src/qemu/qemu_capabilities.c | 2 + src/qemu/qemu_capabilities.h | 1 + src/qemu/qemu_cgroup.c | 10 ++ src/qemu/qemu_command.c | 158 ++++++++++++++++-- src/qemu/qemu_domain.c | 15 +- src/qemu/qemu_domain_address.c | 3 + src/qemu/qemu_driver.c | 1 + src/qemu/qemu_hotplug.c | 1 + src/qemu/qemu_monitor_json.c | 1 + src/qemu/qemu_namespace.c | 3 + src/qemu/qemu_postparse.c | 1 + src/qemu/qemu_process.c | 2 + src/qemu/qemu_validate.c | 6 + src/security/apparmor/usr.sbin.libvirtd.in | 3 + src/security/security_apparmor.c | 2 + src/security/security_dac.c | 8 + src/security/security_selinux.c | 6 + src/security/virt-aa-helper.c | 4 + src/util/virfile.h | 2 +- tests/meson.build | 1 + tests/qemuegmmock.c | 67 ++++++++ .../acpi-egm-memory.aarch64-latest.args | 47 ++++++ .../acpi-egm-memory.aarch64-latest.xml | 124 ++++++++++++++ tests/qemuxmlconfdata/acpi-egm-memory.xml | 124 ++++++++++++++ tests/qemuxmlconftest.c | 8 +- 32 files changed, 672 insertions(+), 21 deletions(-) create mode 100644 tests/qemuegmmock.c create mode 100644 tests/qemuxmlconfdata/acpi-egm-memory.aarch64-latest.args create mode 100644 tests/qemuxmlconfdata/acpi-egm-memory.aarch64-latest.xml create mode 100644 tests/qemuxmlconfdata/acpi-egm-memory.xml -- 2.43.0

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[PATCH 0/3] Fix VMX-* feature detection from MSR
by Hector Cao 01 Dec '25

01 Dec '25

Currently, libvirt is unable to detect the CPU model of recent Intel CPUs (like Granite Rapids) with VMX-* features specified in the MSRs (Model Specific Registers). This is due to the wrong parsing of these VMX-* features from the MSR values. This series of 3 commits allow to fix the MSR VMX-* feature detection. This has been tested successfully on a platform equipped with Intel Granite Rapids CPU. Hector Cao (3): cpu_map: fix sync script to extract correctly vmx-* features cpu_map: update vmx-* features cputest : fix test failures due to VMX-* feature update src/cpu_map/sync_qemu_features_i386.py | 19 +++ src/cpu_map/x86_features.xml | 136 +++++++++--------- .../x86_64-cpuid-Atom-P5362-2-enabled.xml | 10 +- .../x86_64-cpuid-Atom-P5362-enabled.xml | 10 +- .../x86_64-cpuid-Cooperlake-enabled.xml | 10 +- .../x86_64-cpuid-Core-i7-1270P-enabled.xml | 10 +- .../x86_64-cpuid-Core-i7-1365U-enabled.xml | 10 +- .../x86_64-cpuid-Core-i7-8550U-enabled.xml | 10 +- .../x86_64-cpuid-Xeon-6731E-enabled.xml | 10 +- .../x86_64-cpuid-Xeon-6788P-disabled.xml | 1 + .../x86_64-cpuid-Xeon-6788P-enabled.xml | 10 +- .../x86_64-cpuid-Xeon-6788P-guest.xml | 17 ++- .../x86_64-cpuid-Xeon-6788P-host.xml | 17 ++- ...x86_64-cpuid-Xeon-Bronze-3408U-enabled.xml | 10 +- .../x86_64-cpuid-Xeon-E3-1270-v5-enabled.xml | 10 +- .../x86_64-cpuid-Xeon-Gold-6152-enabled.xml | 10 +- .../x86_64-cpuid-Xeon-Gold-6530-enabled.xml | 10 +- ...86_64-cpuid-Xeon-Platinum-9242-enabled.xml | 10 +- ...x86_64-cpuid-Xeon-Silver-4214R-enabled.xml | 10 +- .../x86_64-cpuid-Xeon-w7-3465X-enabled.xml | 10 +- 20 files changed, 181 insertions(+), 159 deletions(-) -- 2.45.2

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[PATCH] NEWS: Mention CVE-2025-13193 and improvements for block stats/config and backups
by Peter Krempa 29 Nov '25

29 Nov '25

From: Peter Krempa <pkrempa(a)redhat.com> Signed-off-by: Peter Krempa <pkrempa(a)redhat.com> --- NEWS.rst | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/NEWS.rst b/NEWS.rst index 879e9e8448..91ed53ba7e 100644 --- a/NEWS.rst +++ b/NEWS.rst @@ -29,6 +29,14 @@ v11.10.0 (unreleased) identification parts of the XML definition (which is needed to perform the checks) and full parsing is done only after checking all ACLs. + * CVE-2025-13193: Incorrect permissions on images after external snapshot of an inactive VM + + The overlay ``qcow2`` images which are created as part of creation of an + external snapshot of an inactive VM had world-readable (644) permissions + which would allow unauthorized users to see contents of blocks written by + the VM after snapshot was taken. Libvirt now sets proper umask so that + the images are created with 600 mode. + * **Removed features** * **New features** @@ -39,6 +47,11 @@ v11.10.0 (unreleased) feature requires Qemu version 10.2.0 or later and is available on Linux hosts where the /dev/mshv is present. + * Add more statistics for block devices on QEMU domains + + The block devices now report optimal access request sizes as well as + statistics such as the queue depth. + * **Improvements** * bhyve: VNC ``wait`` attribute support @@ -57,6 +70,12 @@ v11.10.0 (unreleased) The virt-host-validate tool will now report extra details when certain checks pass. + * qemu: Allow backup jobs to continue if guest OS shuts down + + When starting a backup job users can now use a flag which prevents the VM + to be completely cleaned up if the guest OS shuts down while the backup is + running so that the backup can be finalized. + * **Bug fixes** * ch: Use correct domain definition in chDomainGetXMLDesc() @@ -83,6 +102,13 @@ v11.10.0 (unreleased) if the QEMU binary had it built-in. It is now limited to only platforms with the TDX kernel feature available for use. + * qemu: set ``detect_zeroes`` for all backing chain layers + + Some block jobs (snapshots, block commit) could modify the backing chain in + a way where ``detect_zeroes`` would no longer be honoured. We now set + it for all images in the backing chain, so that it will behave correctly + even after those operations. + v11.9.0 (2025-11-03) ==================== -- 2.52.0

2 1

[PATCH] formatdomaincaps: Fix typo in Hyper-V Enlightenments section
by Jiri Denemark 28 Nov '25

28 Nov '25

From: Jiri Denemark <jdenemar(a)redhat.com> Signed-off-by: Jiri Denemark <jdenemar(a)redhat.com> --- docs/formatdomaincaps.rst | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/docs/formatdomaincaps.rst b/docs/formatdomaincaps.rst index 32dc09d41e..8b4f0ecff3 100644 --- a/docs/formatdomaincaps.rst +++ b/docs/formatdomaincaps.rst @@ -871,7 +871,7 @@ are supported. The ``features`` enum corresponds to the ``<hyperv/>`` element (well, its children) as documented in `Hypervisor features <formatdomain.html#hypervisor-features>`__. The ``defaults`` element then contains child elements describing default values as reported by hypervisor, -e.h. whether direct or extended TLB flushes are available. :since:`(since +e.g. whether direct or extended TLB flushes are available. :since:`(since 11.9.0)` Launch security -- 2.51.1

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